1. Field of the Invention
The present invention relates to a structure of an MNDR device and fabrication method thereof, and especially relates to a structure of an MIS-like MNDR device and fabrication method thereof.
2. Description of the Related Art
In recent years, MNDR devices have attracted much interest for applications in microwave and logic circuits. In the quest to facilitate current circuitry design, MNDR, which can simplify circuitry design and reduce circuitry complexity is of great interest. In practice, multiple-switching behavior of MNDR devices is the main reason that they are so effective. GaAs--InGaAs MIS-like structure with stepping quantum well represents one kind of MNDR device. The related reference is given by : [1] D. C. Y. Chang, C. L. Lee, and T. F. Lei, "Switching characteristics of MINPN devices," Solid-State Electron., vol. 32, pp. 179-189, 1989; [2] S. S. Lu and Y. J. Wang, "A GSMBE grown In.sub.0.49 Ga.sub.0.51 P/GaAs narrow base DHBT exhibiting N-shaped negative resistance with peak-to-valley current ratio up 1.times.10.sup.17 at room temperature," IEEE Electron Device Lett., vol. 15, no. 2, pp 60-62, 1994; [3] C. L. Wu, W. C. Hsu, H. M. Shieh and M. S. Tsai, "A novel .delta. doped GaAs/InGaAs real-space transfer transistor with high peak-to-valley ratio and high current driving capability," IEEE Electron Device Lett., vol. 16, pp. 112-114, 1995; [4] E. F. Schrbert, J. E. Cunningham, and W. T. Tsang, "Perpendicular electric transport in doping superlattices," Appl. Phys. Lett., vol. 51, pp. 817-819, 1987; [5] W. S. Lour and W. C. Liu, "Negative-differential-resistance (NDR) superlattice-emitter transistor," Jpn. J. Appl. Phys., vol. 30, pp. L564-L567, 1991; and [6] W. C. Liu, L. W. Laih, J. H. Tsai, K. W. Lin, and C. C. Cheng, "Multi-Route Current-Voltage(I-V) Characteristics of GaAs--InGaAs Metal-Insulator Semiconductor-Like(MIS) Structure for Multiple-Valued Logic Application," IEEE Journal of Quantum Electrons Vol. 32, No. 9, 1996.